aor'ta

[L. from G. aorte, from aeiro, I lift up.] The main tnmk of the systemic arterial system, arising from the base of the left ventricle; the thoracic aorta is divided into the ascending portion, the arch, and the descending portion; at the diaphragm it becomes the abdominal aorta and bifurcates at the left side of the body of the fourth lumbar vertebra into the right and left common iliac arteries, a. abdomina'lis, the terminal portion of the aorta, extending from the diaphragm to the bifurcation into the common iliac arteries; its branches are the paired inferior phrenic, lumbar, common iliac, suprarenal, renal, and spermatic or ovarian, and the single middle sacral, celiac, superior and inferior mesenteric arteries, a. angus'ta, congenital narrowne of aorta, a. chlorofica, a general narrowing of the aorta a ociated with certain cases of chlorosis. a. thoraca'lis, thoracic aorta, the aorta from its origin to the diaphragm; its branches are the coronary, innominate, left subclavian and common carotid, intercostal, subcostal, diaphragmatic, vas aberrans, bronchial, esophageal, pericardial, and mediastinal arteries.